Growing Watermelon

Best Planting Times for Watermelons in South Dakota

Planting MethodActivityRecommended Dates
Outdoor PlantingIndoor Seed StartingMay 1 – June 1
Transplant OutdoorsJune 15 – July 1
Greenhouse PlantingYear-roundAdjust planting based on temperature control in the greenhouse

Planting Conditions

Watermelon Planting Conditions

South Dakota’s climate varies significantly, with cold winters and warm summers. With USDA Hardiness Zones ranging from 3b to 5b, this creates unique conditions for watermelon cultivation.

Affiliate Disclosure: As an Amazon Associate, I earn from qualifying purchases at no extra cost to you.

Greenhouse Benefits in Cold States

Using a greenhouse in cold states like South Dakota provides a controlled environment for watermelon plants, shielding them from harsh winter temperatures and frost. This allows for an extended growing season, enabling earlier planting and better protection from pests and diseases.

Fertilizer

For optimal watermelon growth in South Dakota, supplementing with fertilizer can ensure abundant and healthy harvests. Quality fertilizer helps replenish nutrients in the soil and promotes vigorous plant growth.
Fertilizer Image
Check out Fertilizer on Amazon

Other planting guides for South Dakota:

Broccoli Planting in South Dakota

Pumpkin Planting in South Dakota

Tomato Planting in South Dakota

Any questions on growing melons? Visit our forum to discuss: Growing Melons.

Plant watermelons outdoors in South Dakota approximately 1-2 weeks after the last spring frost date, ensuring the soil is warm enough for optimal growth.

Average Last Frost Dates for South Dakota’s Major Cities

CityAverage Last Frost Date
Sioux FallsMay 10
Rapid CityMay 20
AberdeenMay 15
BrookingsMay 9
MitchellMay 12

Disclaimer: Frost dates are average estimates, and actual conditions may vary. It is recommended to monitor local forecasts and adapt planting decisions accordingly.

Starting Watermelon Indoors

In cities like Sioux Falls (Zone 4b), begin indoor watermelon seed starting between April 1 and April 15. This timeline ensures healthy seedlings ready for outdoor transplantation starting from late May to early June once the risk of frost has passed.

Transplanting Watermelon Seedlings

Transplant watermelon seedlings outdoors from June 1 to June 15, ensuring the soil has warmed above 70°F consistently. Space the seedlings 36-42 inches apart in rows with at least 72 inches between rows for optimal growth.

General Care and Maintenance

Watering

  • Provide consistent and deep watering to maintain evenly moist soil. South Dakota’s variable climate necessitates regular watering, particularly during hot spells.
  • Water at the base of plants to avoid leaf wetness, which can lead to fungal diseases.

Fertilizing

  • Apply a balanced fertilizer during planting and when the first fruits start forming. Incorporating compost before planting can enhance soil fertility and structure.

Pest and Disease Management

  • Regularly monitor for common pests like aphids, cucumber beetles, and powdery mildew. Vigilance is essential to protect watermelon plants from potential threats.
  • Implement organic or integrated pest management methods to safeguard watermelon plants from pests and diseases.

Harvesting

  • Harvest watermelons when they reach the desired size and color. A dull sound when tapped and a yellow spot on the underside indicate ripeness. Regular harvesting encourages better fruit production.

The importance of good soil

Before starting to grow it is important to take a step back and find the condition of the soil in your garden,The optimal soil is a blend that includes the mineral-rich dirt along with organicrich organic matter that plants need to thrive.


In my garden I try to compost as mutch as possible, so I can mix in the nutrient ritch compost in my soil. I use both hot composting of food scraps and cold composting of all organic garden “waste”..
If you dont have the time or space for composting, it is possible to get compost ready to use in garden centers and Community Composting.
You can read more on Community Composting here: https://www.epa.gov/sustainable-management-food/community-composting

If you are uncertain of the quality of your soil, you can get easy to use soil tests at amazon for 17 dollars. Check latest prices here: Soil testing kit.

Also remember to check out how much sunlight your growing area gets, and that the rain drains well. If you treat your soil well and plan you crops according to your climate you will succeed with any plant you want.

The satisfaction when you harvest your own produce is well worth the time you put in 🙂

BeeJay
Latest posts by BeeJay (see all)